1. Field of Invention
The present invention relates to an air conditioning system, and more particularly to an air conditioning system utilizing a multiple effect evaporative condenser for effectively and efficiently cooling refrigerant.
2. Description of Related Arts
Referring to FIG. 1 to FIG. 2 of the drawings, a conventional condenser 1002P and a conventional cooling tower 1001P for a central air conditioning system is illustrated. The conventional cooling tower 1001P and the conventional condenser 1002P are connected through water pipes 931P, 923P in which cooling water 924P is pumped by a pumping device 932P to circulate between the cooling tower 1001P and the condenser 1002 through the water pipes 931P, 923P. The cooling tower 1001P is usually installed on an exterior of a building, such as on the roof of the building.
Vaporous refrigerant (coming from a compressor of the central air conditioning system) having an elevated temperature enters the condenser 1002P and is arranged to perform heat exchange with the cooling water 924P coming from the cooling tower 1001P. After the heat exchange process, the vaporous refrigerant will be cooled down and transformed into liquid state. The liquid refrigerant 935P is arranged to leave the condenser 1002P and go back to the evaporator for another compression cycle.
The cooling water 924P circulates between the cooling tower 1001P and the condenser 1002P. While in the condenser 1002P, the cooling water 924P absorbs heat from the vaporous refrigerant and the temperature of the cooling water 924P thereby increases. After absorbing heat, the cooling water 924P is pumped backed to the cooling tower 1001P through the water pipe 923P for being cooled down by the cooling tower 1001P. The cooling water 924P having a lower temperature then circulates back to the condenser 1002P through the water pipe 931P for another cycle of heat exchange with the vaporous refrigerant. Conventionally, the temperature of the cooling water 924P leaving the cooling tower 1001P is approximately 32° C., while the temperature of the cooling water 924P leaving the condenser 1002P (i.e. after absorbing heat from the vaporous refrigerant) is approximately 37° C.
The cooling water 924P leaving the condenser 1002P is collected at a top water collection basin 925P. The cooling tower 1001P comprises a tower housing having a receiving cavity, an air inlet 929P and an air outlet 930P both communicated with the receiving cavity, wherein the top water collection basin 925P is provided on top of the tower housing. The cooling tower 1001P further comprises a bottom water collection basin 928P, and a predetermined amount of fill material 926P received in the receiving cavity. The cooling water 924P collected in the top water collection basin 925P is guided (by gravity) to flow into the receiving cavity and in physical contact with the fill material 926P to form a water film. Ambient air is sucked into the receiving cavity through the air inlet 929P and is arranged to perform heat exchange with the cooling water 924P passing through the fill material 926P. After the heat exchange, the air is arranged to exit the cooling tower 1001 through the air outlet 930P while the cooling water 924P is collected at the bottom water collection basin 928P, which is connected to the condenser 1002P.
There exist a number of disadvantages in association with the above-mentioned air conditioning system. First, for the condenser 1002P as described above, the lower the temperature for the cooling water 924P coming into the condenser 1002P, the better the performance of cooling the vaporous refrigerant, and the lower the temperature of the cooling water 924P coming out of the condenser 1002P. For the cooling tower 1001P, however, the higher the temperature of the cooling water 924P collected in the top water collection basin 925P, the more effective the heat exchange between the air and the cooling water 924P flowing through the fill material 926P. In other words, there is a relative relationship between the temperature requirement of the cooling water 924P of the condenser 1002P and the cooling tower 1001P.
Second, referring to FIG. 2 of the drawings, the cooling tower 1001P is filled with the fill material 926P for guiding the water film to perform heat exchange with ambient air flowing through the fill material 926P. Water flowing into the top water collection basin 925P is guided to flow through the fill material (in the form of a thin water film) along a longitudinal direction of the water tower 1001P. Yet from a practical perspective, there is a gradual increase of air temperature between the air inlet 929P and the air outlet 930P because air is drawn from the air inlet 929P to the air outlet 930P. On the other hand, there exists a gradual decrease in heat exchange performance along a transverse direction of the cooling tower 1001P. As shown in FIG. 2 of the drawings, if the cooling tower 1001P is hypothetically divided into four sections, namely W1, W2, W3, and W4, the heat exchange performance in these four sections are different because of their differing air temperature. As a result, the cooling water 924P coming out from these four sections are of differing temperature, yet they are all collected at the bottom water collection basin 928P. Hence, the overall temperature of the cooling water 924P leaving the cooling tower 1001P through the water pipe 931P is actually the resulting temperature of the cooling water 924P after mixing from the four different sections of the fill material 926P (as shown in FIG. 1).
Third, as shown in FIG. 1, the conventional cooling tower air conditioning system requires the use of very long pipes (such as the water pipes 923P, 931P) for connecting the various components thereof. For example, when the air conditioning system and the cooling tower 1001P are installed in different locations, the length of the pipes which connect the cooling tower 1001P and the condenser 1002P must be very long, such that the cooling tower 1001P is typically located at the roof of the building while the condenser 1002P is located somewhere within the building. Such an extensive piping system requires cumbersome maintenance procedures and constitutes substantial waste of raw materials. Moreover, since the ducts connecting the cooling tower 1001P and the condenser 1002P are very long in length, very great resistance will be developed within the ducts so that the energy needed to pump the cooling water circulating between the cooling tower 1001P and the condenser 1002P is necessarily wasted. This substantially reduces the efficiency of the entire cooling tower air conditioning system.